metrics

Prometheus asks your service for numbers on a schedule rather than waiting to be told. That one design choice explains service discovery, exporters, staleness and why short-lived jobs are the awkward case.

Metrics quantify impact, traces expose instrumented request paths, and logs describe individual events. Follow a slow checkout across all three while accounting for missing evidence.

A question with a right answer and a subtle reason. Histogram versus summary is the part that catches people, and it turns on whether you can aggregate across instances.

Champions programmes die as mailing lists with a name. Survivors protect the time, pay in career currency, keep the job description tiny, and measure outcomes rather than attendance.

Discover, scan, deduplicate, prioritise with context, route with SLA clocks, verify, measure. Most programmes rot at dedup and ownership: five scanners produce five conflicting queues nobody trusts.

Percentage savings make every quarter look like a win and tell you almost nothing. A denominator tied to revenue is the one that survives scrutiny, because it is the only one a finance conversation can act on.

You cannot run the counterfactual. What survives scrutiny is a comparison design that narrows the alternatives, not a number that claims to settle it.